I, Bob, have laid down a fairly comprehensive framework for Over-time charting in FMP. FMP's native charting capabilities is very good, but I could find little support for establishing date/time increments along the X-axis. So, I rolled my own. If anyone knows tricks about doing sort of thing let me know. Conversely, I would be happy to share what I have developed.
And BTW, I have bitten the bullet to learn ExecuteSQL to fetch and analyze data for plotting on the chart's Y-axis.